Tools to find bottlenecks in hardware configuration
Solution 1:
If you're running Vista the built in Reliability and Performance Monitoring Tool would give you good feedback on bottlenecks. See Jeffs post on this tool.
Solution 2:
You'd be better off getting a new notebook in some cases .. Memory and Hard Drive are usually the 2 easily replaceable components in a notebook. If you're thinking of replacing the processor or the mainboard, it'd be better to ebay your notebook and pour that cash towards a new notebook. Newer notebooks with good configs are available in the region of 500-600$ nowadays ...
As far as the software goes, you can run a diagnostics check up using the bios or use something like SiSoft Sandra ..