Any form of data transfer to a PC is a potential security risk, from instant messaging to the humble floppy disk. The decision as to what is an acceptable risk is yours, on one hand you could disconnect from the internet and fill your communication ports with epoxy resin, very safe but a touch extreme. If you do decide to try instant messaging, make sure your anti virus is kept up to date. I'd suggest avast! anti virus click here ,fully automated and it has an on access protector that specifically monitors messenger software.