PC OS Boot issue!

[abhinav_sinha]

Hello guys,
I am just making this thread in hope some one might understand my strange problem!:fluriod-confused4:
Actually about one month ago 8th April to be precise when i started the computer it goes up to the point where it says microsoft windows xp and the bars running below it and then it restarted. Then i used ubuntu live cd to see what happened and found that the windows folder was empty. I re formatted it. A few days later again the same problem happened but this time when I used ubuntu I found all files intact nevertheless i reformatted it and again it happened yesterday and I found all files intact and today after I shut down my computer and just half an hour later I tried to start it, it happened again. I have to reformat it and these activities of formatting takes about 3-4 hours. I even checked the boot.ini files but nothing special there it was all correct. An interesting fact that before I formatted my PC yesterday I had Ubuntu installed on it as Wubi and guess what I was able to boot in ubuntu but not in xp.
I even tried to go in safe mode but nothing helps it simply restarts. Also if I boot with XP cd then it shows my C: drive as unknown partition and does not detects any windows installation to which I could have expected to repair.
My PC configuration :: core2duo 2.2 E4500, Intel D945GCPE motherboard, WD 160 SATA HDD, 1 GB RAM, Samsung Dual layer DVD writer.
OS:: XP Sp2, AV:: avast free AV.
I have made no hardware change or driver updates and it ran fine for past nearly 3 yr and i have not installed any new software since then nor updated any except the adobe reader, firefox, and the antivirus. Even these ran fine. In list of new software i use Download accelerator plus but it is almost 3 month when i used for the first time and no problem there. Is there any one who could analyse and tell what the problem is.

[Anish]

It could be the error of the installation CD itself try changing the installation disc.
or try reparing windows by booting in to windows cd and choosing into repair option and in the upcoming terminal type "fixboot"(without the quotes)
or it could be due to any boot sector virus or virus in any other partition of the hard disc, try connecting the hard disc as a secondary disc to another computer and scan it using a good antivirus solution if you cannot boot it.
Use antivirus such as kaspersky, trend micro or k7 these are pretty good.
For free antivirus try avira antivirus

And when restarting whether it shows any BSOD???

[abhinav_sinha]

Thanks for your reply Anish but in case of installation disk error there is no such problem as I have already used it for 2-3 times and nothing special and also i used another copies of it which i made as a backup back from the time i purchased my PC. As for the fixboot how come I was able to boot in ubuntu which i have installed as wubi ? For AV I will surely go for it but but there are lesser chances and no BSOD is there. Although it had come twice while while i was using my pc but I simply restarted my PC and every thing was normal. could this BSOD be my trouble ? How come then I had to format my computer if used it and then just after half an hour it won't start. one more thing yesterday before fomatting when my brother went to shut down the pc it started to install the updated but he simlply turned off the ups could that be the reason because just after that when i tried to start the pc it wasn't. What was the reason that xp was not detecting any windows intallation which even though the files were intact. Also why the disk showed c: as an unknown partition ?