Well first question is did you visit any websites that you should't in perfect world? like torrents sites and so on. If you have some craked software on your pc, there is big change you may have a keylogger of some sort on your pc. To make your pc clean is not that easy, even clean install might not help. So if you planning on investing 10K+ I would suggest buy a new cheap laptop, with official software and you will only use it to trade and access reputable exchange sites and buy encryption software so all your data will be encrypted. This will reduce speed of your laptop a lot so it would not be good to play games but it will be very secure. This is what big IT firms do on their laptops that they give to their workers.
If you can afford to get fresh laptop, you could get a fresh hard drive and do the same, or simple follow what other have said here, clean your pc with malwarebytes, ccleaner defrager and so on. Hope it helps