Hope that helps, kernel panics often resolve with just a safe mode boot and then restart again...unless there is a physical problem such as bad memory but that usually shows up just after installing the memory, not some time later.
Three beeps at startup means there is a problem with the memory,the modules may be faulty or not seated properly.
If you are comfortable working inside your MBP, take the back off and remove then reinsert the memory modules. See it that helps. If not, a visit to the Apple store in Nicosia would be a good idea and have the techs check it and if it is only bad memory, you can see what they will charge you to replace the memory modules.