Help understanding XP error message

This is the error message

BCCode : 19 BCP1 : 00000020 BCP2 : 87F09BF8 BCP3 : 87F09C20
BCP4 : 1A05004F OSVer : 5_1_2600 SP : 3_0 Product : 256_1



My computer was working fine for the past few months and all of a sudden it blue screens and freezes. Then when I sucessfuly restart windows it gives me the above error message log. Ontop of that, I reinstall windowsXP every 3 days because my OS structure gets ruined quickly.

To try to find the problem I have been experimenting with my system . So far I ran Memtest86 for about 2 hours and nothing turned up. Then I updated my norton security and ran virus checks about 3 times alredy. The recently, I replaced my system hard drive hoping that I it was a broken HD. After performing these task I still havent found the problem

I would like to know other peoples opinion.
Thanks