Reinstalling winodws - How much data will I loose?

Formatting will cause you to lose everything. Reinstalling windows over top itself will only over write the windows folder and leave other files intact. You will however have to reinstall all your programs, windows updates, and drivers.

Also, why can't you back up anything? You don't have a spare hard drive? a CD/DVD burner? Anything to backup to?

I bought new PC and my old PC is not working (lost the processor), on my new PC there is 320gb hdd that came with it and my old hdd is a 1tb and I want the 1tb one. I want to have both but the way the pc was made I can't seem to add power to a secondary hdd. So my minecraft world will stay?? (C:\Users\Dale\AppData\Roaming\.minecraft)

No, sorry, user profiles will be lost too - basically any windows related folders get wiped. Your best bet is to install the OS on the new computer. Afterwards install the old drive as a secondary and copy any necessary files from it. Why can't you add power to another drive? Is your PSU that limited? If so, I'd upgrade the PSU.

No its in one of those circle things and it can't reach. Another problem Im having with my new PC is that the audio is ***. Any ideas about that?

circle things?

The power wire is in a plastic circle wrap that keeps the wires tidy.

Circle things? Not sure what you're talking about there. As for the audio, make sure you have the latest audio drivers installed. You can check the device manager to make sure all devices have drivers installed. Ones with missing drivers will have a yellow exclamation point next to them or will be in the "other devices" category.

a tie wrap? cut it and buy a new one.

Windows pro backs up everything into windows.old folder when you re-install the OS.

OMG SERIOUSLY? I will take out my new one and but old one in  .

Only the professional edition does. The home version does not

I can't remember what my old windows version was but the new one is ultimate will it work?

It looks like windows ultimate has all the features of the pro edition, so I don't see why not. When you start installing it, you should get a message saying windows found a previous version and will ask if you want to save the files.

I think installing my old harddrive is going to be too complicated as I don't want to ruin my new PC because I ruined my old one by changing heatsink. Is there a way to retrieve data from my old harddrive without putting it in a computer? Also is 320gb enough for steam games?

You can always put your old hard drive in an enclosure and hook it up via USB or ESATA. As for steam, I guess that depends on how many steam games you have and if you actually keep them all installed all the time.

Be sure to pick an enclosure that has the necessary connection for your drive, SATA or IDE.

http://www.newegg.com/Store/SubCategory.aspx?SubCategor...

Can you recommend a enclosure for 1tb sata form amazon uk? Under £20 if possible. I found this one: http://www.amazon.co.uk/Sata-Hard-Drive-Caddy-Enclosure... but its only up to 500gb.

I like the ones from vantec if they have any. Also, some of their descriptions are out of date as most manufacturers update their hardware to keep up with the new larger drive sizes. I'm not good at currency conversion, so I don't know what is overpriced and what isn't, not to mention I don't know your budget.

Is your hard drive IDE or sata? you need to match interfaces. if it's an IDE drive, you need to make sure the enclosure has an internal IDE connection. If it's sata, it needs an internal sata connection. For the external connection, you want to make sure your computer supports it. Since all PC's today have USB, that's the safest route. If you computer has an ESATA port, that's the way to go since it's faster than USB.

Would this one work with SATA 1TB http://www.amazon.co.uk/gp/product/B000V8KQE6/ref=ox_sc... ?

do you have an external SATA connection?

Nevermind, it's also USB 2.0. That should work

I also found this: http://www.amazon.co.uk/gp/product/B001FB6WPK/ref=ox_sc... Which one do you think I should get?

I've always used enclosures so I really don't have an opinion on a docking station one way or the other.