Glitched Achievment Help

Ok so I got achievments in a couple games and for whatever reason there not achieved anymore. These would be capturing all HVT's in Mercinaries 2 and the Liberty City (5) achievment. I load up my saves both which have the achievments done however im not getting them again. Does anyone know how to fix this?

Thanks

you wouldn't get them again if you had all ready gotten them. and it wouldn't work under a different profile.

...why would you think you'd be able to get an achievement more than once? Is this a joke topic?