Does the screen go blank when you move it when it's plugged in, or is it limited to battery power?
Regarding the battery, I'd double click the battery meter in the taskbar, then go to the "battery information" tab. There should be a button in there for "battery maintenance". You probably want to do a battery reset. I've done this every so often (usually 6 months or so). It will go through a full charge, drain, and charge cycle and reset the battery gauge. It will also bring back a pretty good portion of your full charge capacity, possibly giving you a lot more time on battery power.
I hope this helps.
edit: I'm a ThinkPad user myself. I've used the same R52 for the past 5 years and repaired several internal "faults".