Gnutella Forums - Vista shuts down; can't keep LW going?

Haven't been able to share many of my 2,000+ songs because my new Vista Ultimate shuts down by itself, anywhere from 20 mins up to 90 mins up. Have troubleshot till head aches with no success...does anyone suffer similar problem and is there an answer? Do not want to reinstall because lost a few valuable files last time (???). Just built this system brand new from ground up. If anybody has even a clue or two, please help. Thanks, caseybob
Vista Ultimate 32 w/SP1
Asus M2N-MX SE Plus MoBo
AMD 2 x 64 4200+ w/2GB Ram
2.2GHz clock & nVIDIA 6100 chipset