If the profile you're trying to logon to is corrupted, this can happen. Just boot into Safe Mode, choose the account labeled "administrator", and use that to make a new Windows account. Then see if that works. If it does, move your stuff out of the corrupted account and delete it.
But even in a temporary account you should be able to install new software. Installed software isn't bound to an account, but global.
Kees
I have windows XP Professional which was running smooth til yesterday. Now when I shut down or restart the PC it comes to the WELCOME screen (the blue one) without any problem and then suddenly a new message displays saying- system profile is not present and I have to log on using a temporary system profile. Any changes made in this temp profile are washed off when I shut down the PC and it has to be start all over again.
So I am unable to install new softwares or anything.
What should I do?

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