i've some errors messagesand troubles in internet and messengers.

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try system restore, remember the time when your pc was still ok, then restore it...you can do that by going to Start >All Programs > Accessories > System Tools > System Restore.
or
maybe your pc was infected by a spyware or malware, try to install anti-spyware, try ad-aware by lavasoft, u can download that at download.com, there are a lot of anti-spywares there, don't try to download any anti-spyware that u don't know,it might be a spyware itself,and then install an anti-virus, avg is a good start, but for me avast is better.i will not recommend kaspersky cuz that doesn't work on me..

You can restore to an earlier time when there were no error codes or restore to factory settings, You can do this thru system restore.