Usually with Toshiba models such as this it's normally comes down to needing a DC jack replacement. Toshiba uses really cheap DC jacks and really cheap HDDs. Like the comment above you should test the charge first to rule that out.
Those are usually indicators and codes telling you there is a hardware issue. It is very common with this model to have GPU (Graphics) chip overheating issues. The flashing LED codes mean something: LED Component Error Condition Blinking battery power LED Battery Insufficient charge on the battery Blink: 1 - Caps Lock/Num Lock CPU CPU not functional Blink: 2 - Caps Lock/Num Lock BIOS BIOS corruption failure Blink: 3 - Caps Lock/Num Lock Memory Module error not functional Blink: 4 - Caps Lock/Num Lock Graphics Graphics controller not functional Blink: 5 - Caps Lock/Num Lock System board General system board failure Blink: 6 - Caps Lock/Num Lock BIOS BIOS authentication failure
That sounds like the LCD. The digitizer wouldn't change any coloration. Also take in to consideration if you left this device in the direct sun for a long time or in a vehicle it may be a GPU overheating issue. If not. I'd say LCD. Just my opinion. Good luck.
Most of the time you can go here: http://www8.hp.com/us/en/drivers.html Type in the model and find the driver for Windows XP. If you need the service packs they can be found here: http://windows.microsoft.com/en-us/windows/service-packs-download#sptabs=xp
There is an antenna inside the device that controls the cellular connection. These are very fragile and usually very short and white. You may need to re seat the connection or replace the cable. Unfortunately the only place I've been able to buy them was from over seas but they are cheap. On the other hard. If you used your SIM card or activated another phone (with you current number) while you were repairing the device it will flag the device as stolen to the provider and you will need to call to get it re-activated.
When this occurs it usually means there is a crack in the digitizer somewhere that is not visible to you causing the touch sense to go crazy even when not touching it. You will need to replace the LCD/ Digitizer for starters. They are relatively cheap and easy to replace. I've had this issue before with an iPad. It was in fact the digitizer. Good luck. :)
Sounds like a cable coming off the LCD needs to be reseated. Take the phone back apart and just undo the cables in the top left and then re attach them. Don't take the whole device apart again. It should be a simple fix. Good luck.