Hi onewind
You mentioned changing the power supply . . . did you have a chance to test them (both the old & the replacements)? And though Celerons rarely overheat, did you blow out any dust collecting on the heatsink, check the fans, and check the temps under load?
Try running diagnostics on each part you've tried replacements for. Since most of the hardware that is compatible with your system is reaching end-of-life stage, it's best to test what components you can. The motherboard itself could have suffered some damage (you reference issues with serial and USB port devices). Run a cpu test as well -- if it tests far from the expected ranges, it could be damaged - or misconfigured in the Bios. Most of the hardware diagnostic tools you'd need can be found on the Linux-based "Ultimate Boot CD", a free download --- http://www.ultimatebootcd.com
Especially look in the Bios settings with manual in hand (a search engine should yield a manual) - for advanced Bios guidance, see Adrian's Bios Optimization Guide (the free version)--- http://www.techarp.com/freebog.aspx --- While in the Bios, see if the time/date have reverted backwards several years -- this would indicate that the Bios battery needs replacing (if original, it's overdue for replacement) -- the current battery is likely too weak to hold the correct settings. A 3v coin battery is usually only about $1.50 (USD). If you've never replaced a CMOS battery, here's a generic guide for desktops --- http://h10025.www1.hp.com/ewfrf/wc/document?docname=bph04375&lc=en&cc=us&dlc=&product=94878
Also - boot the system with a Linux live CD (knoppix has fairly light hardware requirements) ... if the system shows the same trouble there: it's definitely hardware.
Best of luck
. . . Gary
You mentioned changing the power supply . . . did you have a chance to test them (both the old & the replacements)? And though Celerons rarely overheat, did you blow out any dust collecting on the heatsink, check the fans, and check the temps under load?
Try running diagnostics on each part you've tried replacements for. Since most of the hardware that is compatible with your system is reaching end-of-life stage, it's best to test what components you can. The motherboard itself could have suffered some damage (you reference issues with serial and USB port devices). Run a cpu test as well -- if it tests far from the expected ranges, it could be damaged - or misconfigured in the Bios. Most of the hardware diagnostic tools you'd need can be found on the Linux-based "Ultimate Boot CD", a free download --- http://www.ultimatebootcd.com
Especially look in the Bios settings with manual in hand (a search engine should yield a manual) - for advanced Bios guidance, see Adrian's Bios Optimization Guide (the free version)--- http://www.techarp.com/freebog.aspx --- While in the Bios, see if the time/date have reverted backwards several years -- this would indicate that the Bios battery needs replacing (if original, it's overdue for replacement) -- the current battery is likely too weak to hold the correct settings. A 3v coin battery is usually only about $1.50 (USD). If you've never replaced a CMOS battery, here's a generic guide for desktops --- http://h10025.www1.hp.com/ewfrf/wc/document?docname=bph04375&lc=en&cc=us&dlc=&product=94878
Also - boot the system with a Linux live CD (knoppix has fairly light hardware requirements) ... if the system shows the same trouble there: it's definitely hardware.
Best of luck
. . . Gary
