Clean slate

Katrina Salter placed her hands on her hips and regarded the mechanoid that had just entered engineering, she recognised him as the droid who told awful jokes at Parrotts bar occasionally, which usually resulted in her getting stupid drunk just so that she could tolerate listening to him.
"Can I help you?" she asked, Sketch 300 opened his mouth to reply but was cut off by Katrina, "And if you start your sentence with "Knock knock" I'll weld you to the outer hull plating."
"Erm…" began the robot, slightly anxious about saying the wrong thing. "I was hoping someone could help in deleting some files from my memory"
"You can't delete them yourself?"
"I'm afraid not, they're read-only..my creator felt it important I learn from my experiences so restricted write access to all memory files once created.."
"Hrm.." Katrina said "Well, sure I can take a look, but if they're read-only it might take some work to get around the safeguards….of course, I'm not gonna do anything unless you tell me why you want them deleted…."
"I broke my programming and made a new life for myself, and don't want to remember anything about the old me" Sketch 300 replied candidly. "Course, I could try alcohol, but it goes straight to my hard-drive!" An mp3 file of a drum roll sounded as he finished the last sentence "Thank you, thank you…I'm here all night!" he said.
Katrina raised an eyebrow. "Is it the bad jokes you want deleted? I'd be happy to oblige if it is…"
"Bad jokes?" Sketch replied "This is top drawer stuff lady, like you're underwear!!" another drum roll. Katrina barely even reacted "…I guess you keep yours in the bottom drawer…." Sketch continued "Look, will you help me or not?"
"Sure…come over here…" she led Sketch over to a computer terminal and sat him in the operators chair, standing behind him, she took a screwdriver from her overalls pocket and began unscrewing the screws holding a his hard-drive access panel in place and removed the panel. "I need to remove the disc, and hook it up to the main terminal to access the files…" she explained
"Ok" replied Sketch "But before you do that, I have something to ask you"
"What?"
"Did you hear about the rabbi who went to th….."
Katrina rolled her eyes and yanked the hard drive out before Sketch could finish his `joke'.
"Hmm" she realised, half an hour later as she gazed at the file list on the hard drive, she'd managed to override the file security quite quickly, but she'd forgotten to ask Sketch what files he wanted deleted exactly.
"I'd better back the whole thing up…" she mumbled, starting the process to do so "then ask him what he wanted done….but hello, what's this?"
There were a handful of what appeared to be corrupted files, "better get rid of these anyway…noone wants corrupted files clogging up their memory…"
She deleted the files from the hard drive, then reinstalled it in Sketch's head, slowly, the robot came back online…
<Tag Sketch, I wasn't sure where you wanted to take this, so I'll leave it up to you, what did Katrina delete, anything important?
Everythings backed up, so don't worry, we can fix any damage>