programs starting late after key stroke

sir, i have a compaq celeron m 1.4 ghz 256 mb ram 40 gb hdd laptop. programs take 7 to 8 sec to start after mouse stroke but once loaded they run fast. iam using tune up utilities to keep my laptop in good shape and also do not have spywares and viruses. 50% of my hdd is free please help me .thanks in advance.