Real CSRSS is an important system process. Some viruses might pretend to be CSRSS, but it's also possible that it's just a buggy driver causing that popup.
Run Task Manager with administrative privileges (open Start menu, type taskmgr, right-click it and choose Run as Administrator) and check how many csrss.exe processes are listed on the Processes tab. You should see two instances of it. If there are more of them, it may be a virus - you should perform a scan using an up-to-date LiveCD scanner, for example Dr. Web CureIt! LiveCD.
If there are only two csrsses, then it's probably just a crappy driver. Laptop manufacturers often include some poor-quality software that's poorly translated and happens to crash quite often.
If you want to get rid of that message, then you should try something like PC Decrapifier to guide you through removing of the Lenovo bloatware.