i recently purchased hp laptop from ebay and it has a power on password which i was gave but has a log on password that i do not know and would like to find out how to bypass this password so i can use the laptop

Can't you get the 2nd password from the seller?

i recently purchased hp laptop from ebay and it has a power on password which i was gave but has a log on password that i do not know and would like to find out how to bypass this password so i can use the laptop
Windows XP stores password information in encrypted files called SAM files. A Google search for SAM file editor will return plenty of results, and you'll find several programs that you can burn to a bootable CD and use to edit these files. I've never personally had to use one of these, so I can't recommend one. Using these editors can render your computer unusable if anything goes wrong. The risk involved in doing this makes an absolute last resort. ANY error in this will corrupt files and LOCK YOU OUT of Windows at best; it will destroy your Windows install and force a reformat at worst.