The following are the steps that would explain my problem:
1. I installed a new 256MB RAM into my system (Pentium 4, 2.4 Ghz, 256MB RAM) and started getting a blue screen sometimes with an IRQL_LESS_OR_EQUAL error. I thought of ignoring it as it would only happen sometimes.
2. Just 2 days after this, I inserted my SANDISK minicruzer flash drive into the back port. The light glowed for sometime and then it went off and the drive was not recognised. I tried using the USB flash in other systems including two laptops but it wouldn't be recognised at all and once or twice it was recognised with a "USB Device not Recognized. One of the USB devices has malfunctioned, etc etc" message coming up.
3. I thought that the USB flash drive had some issues and so forgot about it.
4. After a few days, I borrowed a friend's USB drive since i had some urgent work to do and inserted into the same computer (as in point 1. above) where i was still sometimes getting the "IRQL_LESS_...." error. The same thing happened again and the device stopped responding. I tried it in all the computers i have access to but it wouldnt be detected at all. As before it was detected once or twice but windows gave an error "One of the USB devices has malfunctioned, etc etc"
5. I then inferred that it had something to do with the system in which I had inserted both the SANDISK flash drives. the same system in which I had inserted the additional RAM and used to get blue screen with "IRQL_LESS_...." error.
6. More than the data within, i have lost 2 flash drives.
7. I have gone through umpteens of sites but have not found a solution to this. I even do not know if the flash drives will be usable again or not. So please if any expert can give some opinions, suggestions, workarounds or solutions it would be great contribution to everyone.