Hi Sid.
if the problem were just the monitor, you'd stil be able to here speech without it, indeed, I used my desktop for quite a long while after my first monitor burned out just on computer speakers alone.
if your computer doesn't have separate speakers to the monitor, try plugging headphones into your sound card directly. If you stil here your screen reader and everything seems to be working okay after the grey screen happens you know it's the monitor that has the problem not your computer.
If on the other hand, the hole thing goes down, then either it's a problem with the video card, or a virus. I did once here of a black screen virus that did something similar.
run as many different sorts of virus scans as you can, and also considder looking at some windows utilities such as a registry cleaner (as I've said before I recommend avg's pc tune up program).
Lastly and most importantly though, I'd very much urge you to get an external harddrive for backup purposes.
I myself have a lot of audio, games and music on my pc, and that's not counting my phd thesis work.
If I lost this it would be quite a serious desaster.
I therefore have an external hard drie which I plug into my computer only when I want to back things up, otherwise it sits under my bed in a box.
Being unplugged, it means if I ever got a virus, my backups would be safe, and in fact in 2008 when my desktop's drive completely died, I'd have been in real trouble without itt.
My external drive is a terrabite one, and didn't cost me more than about 110 dollars (actually about 70 pounds), which is deffinately worth it.
It's also very handy for transfering stuff onto my laptop as well.
With our dreaming and singing, Ceaseless and sorrowless we! The glory about us clinging Of the glorious futures we see,
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)