shut downs

[solarpuppy]

immediately after the auto update installed SP-3 on my Windows XP Home , I started getting an error . ( signature BBCode : 10000008e ; BCP1 : C0000005 ; BCP2 : 8054B815 ; BCP3 : B4280A98 ; BCP : 00000000 . ) my computer reboots approx every 15-20 minutes , regardless of me using it or it's sitting idle . Any suggestions as how to fix this problem ?
Thanks in advance .