if it was cleaned properly this should have eliminated an overheating problem unless the techie did not clean it or check that oine of the fans was not operating at the correct speed. The next simplest thing to do is to change the power supply as this is a quick relatively inexpensive operation. You could easily do this yourself. Note the rating of the psu and as long as the one you get is equal or has a larger rating that will do the job. Next follow each cable from the psu to the motherboard and note the number of connections. Also note the power connectors to the optical and hard drives. These could be either the older white 4 pin almost rectangular plug with slightly rounded corners on 1 long side or the newer sata connections which are very much smaller with a thin slot with a right angled tiny slot at the end.