Try the following it could help you out:
Select My Computer -> Properties -> Advanced -> Environment Variables -> User environment variable
Set TEMP and TMP to c:\temp
16 bit applications can't manage the spaces or long file
names, and will generate ntvdm errors, even if they are not
explicitly referencing the TEMP directory.
If the above won't work then check Microsoft:http://support.microsoft.com/kb/314106
Finally:you should try a registry Repair & a Malware Scan