USB drives/keyboard and mouse not working

What file did you install? It would be helpful to know what borked your pc

Win7 you should be able to get into it by pressing f8 a bunch of times on PC boot (BEFORE you see the windows screen or you're late). As in right after you see post text come up and go away, no harm punching it early repeatedly. That gets you into advanced boot options where you can choose REPAIR and get to system restore options. XP/vista same thing to get to boot menu (but only 7 includes repair by default). Your keyboard should still be alive to get a F8 key in as it likely isn't going belly up until you get past this and whatever is screwing you starts loading.

You can also use your windows CD/dvd (your windows install disc I mean) to get to repair options. Stick it in and boot from the dvdrom. You should be able to hit a key during post to get to an advanced boot menu in most cases as opposed to directly forcing boot from dvdrom in bios settings (which takes longer and know-how). There are vids on the bios changes if needed on youtube. Once booting from it you'll get a message saying "to boot from cd hit any key" or something like that, do so quickly to boot from disc.

On the System Recovery Options menu, click a tool to open it (system restore if you had it on and have some restore points to go back to). Startup repair might work, but system restore is probably going to work here (whatever works).

Is that enough? Got a system repair disc you created earlier when you had windows running (why doesn't anyone make these immediately after an install?)? You can use that too.

Win8 makes it more difficult since it has a very small window. Just another reason 8/8.1 sucks
http://www.7tutorials.com/5-ways-boot-safe-mode-windows-8-windows-81
Win 8/8.1 help there.

TOUCHDOWN!...LOL. Glad to see you back up. No need to panic, there are tons of brains in here to help you and many are highly qualified techs in daily jobs doing this stuff Very odd with poweriso issue but not shocked. If for some reason that is just cast out now (still OK to use after fixing the drivers?), I've used alcohol 120% (good burning app also) for the same thing and in fact I have both installed, just using poweriso for now which is great for extracting data from the images etc. I have a 1/2 dozen burning apps installed (shocked that doesn't cause some issues...LOL) Each for different jobs (imgburn is best! and free, tons of users/help).

I used to like daemon tools for virtual drives but kept running into issues with the latest ones with other apps or just me plugging/unplugging so many external drives plus a few flash drives (I think it freaked or something, I have well over a dozen), so went to others for this job. Alcohol and poweriso seem equal for this purpose. My dad's PC has alcohol, and likes it also and he's not a total nerd these days so it isn't that hard to use. I've also had experience with slysoft stuff for this which always worked fine too. I used to have to try all kinds of crap to support customers so I use much more apps covering the same stuff than most.

You might want to use Virtual PC (microsoft free tool) for mounting images of your own PC to test crap without worry. Virtualbox is out there too for this, here's both links.
http://www.virtualbox.org
http://www.microsoft.com/en-us/download/details.aspx?id=24439
32 or 64bit. Just a thought if you've never went down this road.
http://www.vmware.com/products/player
Also vmware player can be used. All 3 allow you to mount an image of your PC and do dangerous crap in there and if it screws up you just delete the file and copy the original image back to your drive and go again and again...Nice. So you make your system image then copy it to external or something so you can just keep replacing it when you mess up the file on your local drive doing something you don't want to test in your REAL OS. From an SSD they can load fast too. An xp image is small and can be used for all kinds of testing (if you don't have space for a win7, xp, vista, win8 collection xp is perfect for testing crap, vhd (ms), vmdk (vmware image) etc images can be mounted with the 3 tools mentioned). I won't go into how to use these 3 here, as anyone can likely google the tool name and find vids for each on youtube which is easier than typing it all for each. I'm just giving the links here for people who don't realize this stuff exists, you can take it as far as wanted after that.

http://technet.microsoft.com/en-us/magazine/ee872416.aspx
How to create VHD in win7. Note last I checked virtual pc couldn't mount a 64bit image (though the app comes in both 32/64 flavors not image support), so YMMV on that tool hence the other two options. Hyper-V covers that on MS side.
VirtualBox 3.2.+ can run 64bit 7 or Server 2008, vmware can host 64bit environments also. IMHO both are better than virtual pc (xp mode etc, whatever). XP Mode is only available for Windows 7 Professional, Enterprise, and Ultimate. But that doesn't stop you from using the others etc

Forgot another usable virtual cd app.
http://www.dvdfab.cn/download.htm
http://www.dvdfab.cn/virtual-drive.htm
Another free one. DVDfab virtual drive. Not sure how good that is, I don't use that though I have the dvdfab installed and they make some great products for many ripping/copy jobs.

Before I forget, make a system repair disc and maybe a full system image also (windows backup etc) System restore is always supposed to make a new restore point on app install but I never trust it myself and do it MANUALLY when doing anything that isn't a MS update (they get that right and always make one for these). I've seen too many times where other app installs oddly haven't made the restore point behind my back like its supposed to. So I do it myself, then install my app. Just a precaution.
http://windows.microsoft.com/en-us/windows7/create-a-system-repair-disc
how to make repair disc.

Hope that helps anyone who doesn't want that dreaded OOPS moment Of course it goes without saying we should all have a comprehensive backup strategy in place too. Everyone should install Threatfire if they don't have it also FREE & awesome on top of any AV suite and is very quiet with low resources used (basically none, 0% cpu most times, rock stable never a crash). These are all very well known apps, google reviews if worried. Threatfire is recommended by pcmag etc and I've installed it on top of just about every av suite out there for customers over the years.
www.pcworld.com/article/254748/pc_tools_threatfire_free.html
http://www.pcmag.com/article2/0,2817,2347573,00.asp

Understand it goes on top of, does not replace your AV. It pops up every few weeks or so to try to tell you to buy pctools and give you a statistics report but you just close it (it's a status report really that's all). Small price for such an effective app or you can elect to turn off the automatic report in General Settings. Some may want the info that pops up though.
http://www.threatfire.com/updates/
Can get info and download from there. Stay safe people