Hi lvgandhi
Following Jahans advise - Since you said you were unable to restore your PC to any of the available restore point date opitions – I suspect your PC is infected,
and may be the infected file is preventing you from using the restore option.
I strongly suggest to not use this PC for Internet banking , check your emails and other websites/applications which you believe might get compromised. And also change your passwords wherever necessary (banking etc) using your Laptop. It is better that you format (C Drive) and reinstall OS of your choice (ideally the latest or at least W.XP SP3).
Alternatively, if you do not want to go for it now and still want to use your PC than Dan’s advise is the best. Try using CCleaner (or trial version of System Mechanic or Tune Up Utilities – all three do the same except that the latter 2 have extra features) followed by RKill.
It usually happens that after a system has been used for a considerable amount of time, without proper maintenance, the system is cluttered with broken shortcuts, obsolete or damaged registries and defragmentation, hard disk error etc. CCleaner helps repair this issue. I have not used CCleaner or RKill but I believe together they both do what System Mechanic or Tune up do.
By the way you did not mention using any antivirus S/F other that scanning with microsoft security essentials?
NOTE:
Before you format your C Drive take a back up of all files that you feel is necessary. It is always better not to use C Drive to save/store your important files other than installing your S/F programs.
Extra Info [Links]:
1. Nearly 50 percent of Indian computers affected by virus between April and June 2013: Kaspersky
http://www.bgr.in/news/nearly-50-pe...-virus-between-april-and-june-2013-kaspersky/
2. Keystroke Logger Virus
http://www.securelist.com/en/analysis?pubid=204791931
[Even after taking all possible precaution we are vulnerable to threats in this fast changing IT world. But then it is better safe than sorry.
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