[B][U]H/W Diagnostics:[/U][/B][B][U][/U][/B]
Please start by running these hardware diagnostics:
http://www.carrona.org/memdiag.html (read the details at the link)
http://www.carrona.org/hddiag.html (read the details at the link)
Also, please run one of these free, independent online malware scans to ensure that your current protection hasn't been compromised: http://www.carrona.org/malware.html (read the details at the link)