laptop suddenly accepts only one key

hi

i just bought a new laptop with XP . The problem is sometimes it suddenly accepts only one key , and if u type the next key it opens up some application ( for eg. if i press A and R it takes A , and then it opens up the run window.)
Once this starts happening it happens everywhere,( explorer address bar, if u try to name a new folder etc.)

The only way to stop this is to restart the machine. can anyone tell me what the problem could be ? and once it happens how do i get it to function normally without having to restart it ?