Random Crashes

[Mesmerize]

O.P.All right, here's the situation:

Acer PC, running XP Media Centre. AMD Dual Core 64 bit, 1 gig ram, 250 gig HD. About a year old, maybe not even that.

A while back, for no discernible reason, it started to repeatedly crash. I'd boot it up, and it would freeze at the login page, the welcome page before/during/after the windows login tone, with the desktop partly loaded (everything except the start bar) or with the desktop fully loaded, and about every place in between. The occasional (read: 20th) attempt produced a normal startup. Then I'd restart the computer and it would happen all over again. I've had a technician in, he can't find anything wrong (other than the freezes). I've defragged, chkdsk'ed, CCleaner'ed, Spybot'ed, and AVG'd the hell out of it. I used an OEM disc to do a chkdsk and repair through the recovery console and now it runs maybe every 5 tries. I thought it might be a surface error or bad sector on the disc, but apparently not. It (the problem) doesn't look like any worm or virus I've ever heard of. Not many programs to load, the C:\ partition is full of space, no spyware/adware that I can see. I had CCleaner clean the registry, that seemed to speed it up when it worked.

So in my mind (and I am no means an expert, I can use windows with the best of them but I know nothing about coding, programming, the workings of windows itself), I have some sort of corrupt sector in the registry or the windows install itself has been corrupted. The technician gave me a tutorial on doing a repair on windows with the OEM disc. As follows:

OEM disc in
boot menu, boot CD-ROM
press enter at 1st prompt
press F8
select "R" option

Problem is, A) I can't see anywhere to press F8 or choose the R option, and B) I didn't write the directions down clearly enough, so I'm probably doing something wrong.

If you guys have any ideas, or need to ask some questions, feel free.

I was hoping that somebody could recommend me a good registry cleaner that can detect corruption in the windows section (as opposed to unused extensions, etc), because somehow I don't think CCleaner can do that.

Thanks for the read and the help!

:UPDATE: I don't think the registry is the problem anymore. The RAM is fine; I ran Memtest86.

I ran chkdsk on my D: partition. (ACER computers come partitioned, half and half, windows installed in C It said that "There appears to be unrecoverable errors on this drive" (presumably D:, seeing as that's the one I scanned).

Question, why would D:, the partition without any parts of windows installed in it, with only media and some games installed on it, be causing the computer to crash?

NOTE: The My Documents section for both users (me and my brother), is on D:. Not sure if that includes settings, etc.


Do you guys have any ideas?

Oh and the repair option in the Windows XP setup from the OEM will not come up. Not sure why, but possibly because windows is not recognizing the install properly.