Bites za dust

Hey guys so I just applied some thermal paste to my cpu couple months back actually a guy applied it from whom I bought the cpu and the cooler from at the time I didn't notice that the cooler was dirty and now i want to know if i remove the cooler and clean it (the heatsink and fan part) and fit it in the system again .. will the old thermal paste still work or do i really have to order some more thermal paste

Ok thanks guys for the advice.. ill buy the rx560 for now and the next thing ill do in a couple months maybe is buy a branded and reliable powersupply..

Hey guys, so i have a question currently in my pc I have a 600w Cheap chinese powersupply which i bought for 35 $ on ali express in winter (at the time i didn't know much about psu) and now im stuck with it .. recently I found a good deal on a rx560 I was thinking that if I buy it and put it in my system will the psu be fine or pop or something and take my system down with it (keep in mind that I can't really spend more money on psu they're quite expensive in my country and im a senior highschool student). I've watched a video on a tech youtuber explaining how to spot a bad psu according to what he said I personally think it would probably work fine but I wanted to know what you guys think since you all are Experienced so kindly tell me if i can get that rx 560 or not? .. https://youtu.be/SX0LjqdGvxs The video link My current specs are Xeon x3440 4gb ddr3 1333 ram Hd 5450 512mb (planning on getting rx 560) Wd 300GB hdd 7200rpm Thanks in adv :)