Strange memory usage results in corrupted OS?

[zooyork19]

Well a few days ago, every time my computer was up for more than 3 hours the memory usage would be around 80-98%, with 8Gb of ram. This happened around the time I tried kaspersky AV with a trial version. I would continually try to update while I was gaming so I turned it off, as I'd had a lot of issues with it crashing my computer whenever I tried to update or exit it. So I set it to never update or search for viruses without me telling it to, until I could remove it. Because of this I was forced to hold my power button down to restart around 3 times. Then I started noticing the memory problems. Figuring it was a leak in a game I've been playing I didn't think nothing of it. I woke up one morning to 89% usage and figured I'd do a restart. When it tried to boot it gave me a boot disk error, so I put my windows cd in and set the drive as my top priority boot device. But now it just hangs at the boot up screen (asus logo along with del to enter BIOS) I can enter the BIOS and change the settings but whatever I do it just sits there, once it went on, but only to come back with the same exact error, assuming it didn't find the disk and tried from the HDD again. Also, it takes a couple minutes to even enter the BIOS, which has never happened before.

Running an E8400 CPU
GTX 260
8GB of RAM
and an ASUS P5N-T Deluxe Motherboard.

I have a backup windows disk and that wont work either, both of which I've tested and used before to install windows. I am out of ideas and before paying to get this thing fixed I'd rather see if there are any other ideas. Anything is appreciated and could save me some money. Thanks for reading.

 

[zooyork19]

Well, the problem was a faulty hard drive. Popped a new one in and reinstalled windows no problem. Hope this helps someone because apperantly no one on here can.