Firstly i am new here and i have searched up many forums and such regarding this issue. But i want to be specific about this question.
Say that i have infinite amount of time and i’d like to render a very huge scene in blender without crashing it. Is it possible? i mean that i dont want blender to use all my computer speed to do this job, all i want it to do is use a little bit and do the job for however long it takes. So is such thing possible? because the problem is that i have a very low end system but would like to get the best renders. all i do is still image renders so time wont be a problem.
Hope the question makes sense and also i am beginner so go easy on me when you are giving out details. 
these are my PC specs.
Windows 8 64 bit dell inspiron
4 gigs ram
2.4 Ghz intel Pentium processor
intel hd graphics-1664 MB memory
thanks